Insulation



- Jan. 5,1937. c. G. MUNTERS I 2,067,015

-INSULATION Filed DSC. 5, 1934 .1N ENTOR,

lPatented Jan. 5, 1937 UNITED STATES NT OFFICEl s signor AktiebolagetTermisk isolation, Stockholm, Sweden, a corporation ci SwedenApplication December 5, 1934, Serial No. 756,051

Sweden March 3, 1931 9 claims. (ci. 154-44) This application is acontinuation in part of my copending application Serial No. 595,411filed Feb. 26, 1932, and is to be considered as relating back to saidapplication for common subject 5 matter and the rights incident thereto,including the rights incident to filing a corresponding application inSweden on March 3, 1931.

The invention relates to insulation and the bject is to provide aninsulation having better heat transmission negation than that ofstagnant air and other ordinary insulations. The nature of the inventionwill become apparent from consideration of the following descriptiontaken in conjunction with the accompanying drawing I 15. forming part ofthis specification, and of which:

Fig. 1 is a transverse sectional view of insulation embodying theinvention; and

Fig. 2 is a sectional view of a receptacle insulated in accordance withthe invention. 2o The' insulation wall 5 shown in Fig. 1 is made of anouter wall structure which is hermetically sealed and is filled with apowder, granulated material, a brous mass or the like. There is alsosealed within the wall structure a gas havingpoor heat transmittingability, for example, a compound including sulphur and/or a halogen.such as dichloro-diuoromethane or sulphur hexafluoride. The solidmaterial within theA lnsulation wall serves both to counteract heattransmission by radiation and heat transmission by convection of the gascontained therein. As a filler, powdered glass, siliceous earth,glass-wool, powdered charcoal, granulated cork, or cork powder may beused. l

The walls 6 which are transverse to the direction of flow of heat are.made of metal. The walls 1 which extend in the direction of iiow ofheat should be made of material of poor heat transmitting ability andfor this purpose cellon (a mixture of acetocellulose and camphor or likeplasticizers) or a metal alloy such as nickelsteel may be used. A nickelalloy-comprising 30 to 40 per cent Ynickel has proven to besatisfactory. Obviously all of the walls 6 and 1 may be made of anickel-iron alloy. I preferably make the walls l which extend in thedirection of heat flow of extended length as shown in Fig. 1 in order todiminish the heat flow. It might be mentioned that sulphur hexafiuoridehas a heat transmitting capacity which is only a third or a fourth ofthat of stagnant air. Furthermore this gas is chemically inert to theother substances mentioned and has a low diffusion' capacity which makesit relatively easy to hold this gas within 55 thedwalls of theinsulation. 'I'his is especially true if the walls be made in whole orin part of cellon. The gas may be charged into the casing structure soas to have a pressure at or somewhat below atmospheric pressure. Whenthe gas has a pressure below atmospheric, the ller prevents the wallsfrom collapsing. I

In Fig. 2 I have shown the application of the insulation to a container.The container, which may be used for storing food, and which constitutesin effect a tireless cooker, is composed of a lower part I5 and an upperpart I6, the upper part serving as a lid or cover for the lower part.Both parts are provided with walls I1 which may be of metal. These wallsmay be enameled. The wall parts I9, where the two parts of the containermeet, and which constitute heat conducting paths between the outer andinner walls of the respective container parts, are preferably made of amaterial of low heat conducting capacity. For this purpose anickel-steel alloy may be used. vAlso these wall parts I9 'are made verythin. In order to support them against buckling due to the internalpartial vacuum, in addition to the porous mass 5 contained within thewall structure hoops or rings may be provided constituting stiffeningmembers for the wall parts I9. vThese walls are made conical tofacilitate closing the container. V

The horizontal walls, namely, the upper and lower walls, may bereinforced as by parallel plates 2| which can be held spaced by pins orthe like 22. The two parts of the container may be held together bycleats or the like 24. The parts are hermetically sealed as described inconnection with Fig. 1 and contain a powdered or iibrous material, forexample, glass, carbon, ground cork or the like and the interior isfilled with gas of poor heat conducting ability. Vessels for food may beplaced. within the container, and 26 designates a bottle.

Besides sulfur hexauoride (SFc) the dichlorodiiluoromethane (CClzFz),other gases which may be used within the insulation are methyl chloride(CHaCl), sulfuryl fluoride (SOzFn), methyl bromide (CHsBr), and ethyliodide (CzHsI). All these gases are halogen compounds. Other suitablegases for certain insulations are compounds of sulphur such as sulphurdioxide (SO2) and carbon disulphide (CS2). A mixture of two or more ofsaid gases may be used. The gas or gas mixture which is made use ofshould have a boiling point lower than the lowest temperatureprevailingwhere the heat insulator is to be used. The gas chosen should beinsoluble in the material of which the insulation is made and should notreact with said material. Each of the substances mentioned has a lowerheat conductivity than air at a corresponding temperature and pressure.n

Only a total internal pressure of about 0.1 mm. Hg need be produced forobtaining about the same insulation effect as present in a thermosbottle.

What I claim is:

1. Heat insulation comprising a hermetically closed element whichcontains a gas having a lower heat conductivity than that of air atcorresponding pressure and means counteracting heat transfer due toconvection and radiation, the outer and inner members of the elementbeing made of metal and the transverse walls connecting said membersbeing of poor heat conducting material and having a length greater thanthe shortest distance between the members they connect.v

2. A hermetically sealed insulating element having opposite wallsconnected by corrugated walls of low heat conductivity and a gas of lowheat conductivity confined within said insulating element.

3. Heat insulation including walls extending transversely to thedirection of heat flow and walls extending in the direction of heatiiow, said walls being of metal and at least the second-mentioned wallsbeing of metal of poor heat conductivity, the walls being securedtogether to form a hermetically sealed casing, and a solid nnely dividedmaterial in said casing of a character to resist compression, saidcasing being lled with said material and being at less than atmosphericpressure inside the same whereby said material prevents the walls fromcollapsing, said material constituting the only staying means within thecasing between opposite walls thereof.

4. Heat insulation including walls extending transversely to thedirection of heat iiow and walls extending in the direction of heatflow, said walls being of metal and at least the secondmentioned wallsbeing of metal of poor heat conductivity, the walls being securedtogether to form a hermetically sealed casing, and a solid finelydivided material in said casing of the character of powdered charcoal orsiliceous earth, said casing being lled with said material and being atless than atmospheric pressure inside the same whereby said materialprevents the walls from collapsing, said material constituting the onlystaying means within the casing between opposite walls thereof.

5. Heat insulation comprising a hermetically closed element which isinteriorly under sub-atmospheric pressure and contains a filler, theouter and inner members of the element being made of metal and the wallsconnecting said members being of poor heat conducting material andhaving a length greater than the shortest distance between the membersthey connect, said iiller staying the walls of the element againstcollapse.

6. An insulation member including spaced walls extending transverse tothe direction of heat flow and connecting walls in the direction of heatow, said walls being connected to form a hermetically Y sealed casing,one or more of said walls being such that the casing is collapsible onpreponderance of external pressure, said casing having a pressure belowatmospheric within the same, and a nely divided filler within saidcasing for hindering fiow of heat and preventing the casing fromcollapsing.

'7. An insulation member including spaced metal Walls extendingtransverse to the direction of heat iiow and metal walls extending inthe direction of heat fiow, said walls being connected to form ahermetically sealed casing, said lastmentionedwalls being longer thanthe normal distance between the first-mentioned walls and of suchconstruction that the casing is not selfsupporting under preponderanceof external pressure, the interior of said casing being undersubatmospheric pressure, and a finely divided ller in said casing forhindering heat ilow and preventing the walls from collapsing.

8. A hermetically sealed insulating element having opposite wallsconnected by corrugated walls of low heat conductivity, the interior ofsaid element being under subatmospheric pressure,

and a ller in said element for staying the walls against preponderanceof external pressure.

9. An insulation member as set forth in claim 6 including at least oneconnecting wall of thin nonconducting material and of appreciable width,and means for staying said connecting wall.

CARL GEORG MUNTERS.

